On November 3, 1956, The Wizard of Oz—a film made and released in 1939 by MGM—made its television debut. CBS paid MGM $225,000, a huge amount in ‘56, for the rights to televise the film and to re-broadcast it if the telecast was a success. And what a success it was, becoming the most-watched film of all time as families still gather around their TV sets each year to sing along.

The timeless tunes were written by Harold Arlen and his lyric partner E.Y. Harburg who were assigned the job of scoring Frank Baum’s children’s classic. When they’d finished what Arlen called the “lemon drop” songs (“We’re Off to See the Wizard,” “Ding Dong! The Witch is Dead”) the pair turned their attention to a show-stopping ballad. “I felt we needed something with a sweep, a melody with a broad, long line,” Arlen said. “Time was getting short, I was getting anxious. My feeling was that picture songs need to be lush, and picture songs are hard to write.”

The ballad came out of the blue one day while Arlen and his wife were headed to a movie at Grauman’s Chinese Theater. He jotted down the melody in his car while driving on Sunset Boulevard. “It was as if the Lord said, ‘Well, here it is, now stop worrying about it!”

“Over the Rainbow” was his crowning achievement, a song that has come to be, in the words of Judy Garland, “symbolic of everyone’s dreams.” In 2003, it was voted number one movie song of all-time by the American Film Institute.